Refrigerator with a pressure-compensation valve

ABSTRACT

A refrigerator with a body and a door attached to the body wherein the body and the door delimit a thermally-insulated interior space, the refrigerator including a pressure-compensating valve for controlling an inflow of air from the outside of the refrigerator into the interior space and an outflow of air to the outside of the refrigerator out of the interior space to the outside of the refrigerator, wherein the pressure-compensating valve is disposed in thermal contact with a heat source and for heating the pressure-compensating valve to a temperature greater than the freezing point of water.

The present invention relates to a refrigerator such as a domestic refrigerator or freezer with a pressure-compensating valve that serves to prevent the development of an underpressure in the interior space of the refrigerator.

Each time the door of a refrigerator is opened, warm air enters its interior space and after the door is closed cools down in said interior space and generates an underpressure by which the door is sucked in against the front side of the body. After the door is closed, this underpressure makes it very difficult to open it again until the pressure between the interior space and the environment is again equalized. In fact, pressure compensation is always restored after a prolonged period of time as the seal usually fitted between the door and the front side of the body of the refrigerator does not provide a completely airtight seal, so it is generally necessary to keep the leakage rate of this seal as low as possible since, due to leaks in the seal, air which is exchanged between the interior space and the environment also continuously results in undesirable ingress of heat and moisture into the interior space. The more accurately the refrigerator is manufactured and consequently the lower the leakage rate, the longer the underpressure is maintained after the door is closed.

In order to solve the problem, various door-opening servo-mechanisms have been suggested which, via a lever mechanism or the like, reinforce the tensile force exerted by a user on a door handle to open the door by separating the door from the body against any underpressure prevailing in the interior space.

Such types of door-opening mechanisms inevitably include moving parts which are subjected to considerable forces during operation, thereby resulting in wear and malfunctions.

To enable the door to be easily opened at any time, it has also been proposed to fit in the wall of the housing of such an appliance a pressure-compensating valve which, in the event of underpressure prevailing in the interior space, permits air to flow from the outside to the inside and blocks it as soon as the pressure between the environment and

interior space is equalized, so that an uncontrolled ingress of heat and moisture into the interior space is eliminated.

It has been shown in practice that such a pressure-compensating valve has a tendency to freeze solid during the operation of the refrigerator, so that pressure compensation via the valve no longer takes place.

The object of the invention is therefore to create a refrigerator with a pressure-compensating valve between the interior space and the environment, in which the risk of the pressure-compensating valve freezing solid is eliminated or at least minimized.

The object is therefore achieved according to the invention by placing the pressure-compensating valve in thermal contact with a heat source, which permits the pressure-compensating valve to heat up above the freezing point of water.

Surprisingly, it has in fact been shown that the freezing-up of the pressure-compensating valve is not usually attributed to airflows which always flow through the pressure-compensating valve after the door is closed, but rather that considerably slower airflows are the decisive factor in this case. Even if the door remains closed, the temperature of the interior space of the refrigerator is not precisely constant but periodically fluctuates and each cooling is associated with an inflow of air into the interior space, whereas during heating-up air flows out, that is to say it can be pictorially expressed as the refrigerator “breathing in” and “breathing out”. Whereas during pressure compensation after the door is closed the air rapidly flows through the pressure-compensating valve and moisture contained therein has little chance of settling in the valve, the inflow during the “breathing in” is considerably slower, so that the inflowing air has already cooled down in the pressure-compensating valve and its moisture condensed therein, with the result that the moisture freezes out and the valve loses its mobility and is blocked.

Formation of ice in the valve and thus its inability to function can be reliably prevented by direct or indirect heating of the pressure-compensating valve. One possible way of heating the valve to above the freezing point of water is by arranging the pressure-compensating valve in the region of so-called refrigerator frame heating.

Such a frame heating arrangement is provided in many refrigerators so that by heating the frame which forms a thermal bridge between the interior space and the environment, the outer surfaces of the body and/or of the door adjacent to the frame are prevented from cooling down so severely that moisture condenses on them. Freezing-up of the valve can be completely prevented without additional manufacturing outlay by placing the pressure-compensating valve in thermal contact with the frame heating.

A favorable position for the valve, in which it is effectively heated by the frame heating, is in an area of the door that is opposite the frame.

If, in the known manner, the frame has a ferromagnetic strip opposite a magnetic door seal, it is useful if this strip has a locally widened section opposite to the pressure-compensating valve. The good thermal conductivity of the strip can thus be used to effectively heat the valve.

It is also useful if the pressure-compensating valve is placed in one corner of the door, since the corners generally represent the least cold areas of the door.

The frame heating preferably includes piping through which compressed refrigerant passes. Such frame heating is in fact only effective for heating the pressure-compensating valve when a compressor, which supplies it with the refrigerant, is operating at the same time, but this in no way impairs the effectiveness of the frame heating as protection against freezing-up of the valve. If the compressor is not operating and consequently the interior space is not cooled, it warms up slowly. During this time, the frame heating may possibly not be able to prevent the pressure-compensating valve from cooling down to below the freezing point, but the simultaneous heating-up of the interior space prevents air from flowing through the pressure-compensating valve into the interior space, whose moisture could condense in the pressure-compensating valve. Also during this period there is therefore no risk of icing up. If the compressor operates again and the interior space cools down, air can indeed flow again through the pressure-compensating valve, but at this time the pressure-compensating valve is heated by the frame heating.

If one wall of the body or of the door in which the pressure-compensating valve is fitted, includes in the known manner a solid outer skin, a solid inner skin and a layer of insulating material enclosed therebetween, a simple and low-cost mounting of the pressure-compensating valve is possible if this is accommodated in a tube passing through the layer of insulation material and tightly sealed at the outer skin and the inner skin, it being possible for the tube to have two interlocking sleeves, one of which is tightly attached to the outer skin and the other tightly attached to the inner skin. By sliding them in the longitudinal direction, the interlocking sleeves permit convenient adjustment to differing or varying housing wall thicknesses. Each of the sleeves can be individually fitted to the outer skin and the inner skin, even if the distance between the two is variable.

Preferably, the outer of the two sleeves has a conical inlet section which opens into the layer of insulating material. This inlet section facilitates the fitting of the valve by facilitating the mutual insertion of the two sleeves. This is particularly important when assembling the wall which contains the valve. If initially one sleeve is attached to the outer skin and one sleeve to the inner skin of the wall, respectively, then their ends facing each other have to be inserted into each other before the outer and inner skins can be interconnected. This mutual insertion is facilitated by the widening.

If the outer of the two sleeves encloses at least one part of the length of the inner one with some play, to mutually seal the sleeves, on this part the inner sleeve is preferably enclosed by a first annular lip fitted to the outer sleeve.

This lip is preferably concave on one side facing the layer of insulating material, so that due to the pressure of the expanding insulation material it is pressed against the outer sleeve, which assists the tight connection of the lip to the outer sleeve.

The sleeves can be attached to the inner or outer skin whereby the sleeve is inserted through the relevant opening and supports projections on an outer side of the outer skin or inner skin, and a second annular lip on an inner side of the outer skin or inner skin facing the layer of insulating material. The outer or inner skin is therefore clamped between the projections and the circular lip, and at the same time the lip prevents the insulating material from reaching the edges of the opening and emerging at these.

The valve preferably includes a bent flexible blade accommodated in the inner sleeve and with edges in contact with the inner side of the sleeve. Provision can be made to secure the blade in the sleeve by means of a bar extending diametrically through the inner sleeve, the blade sitting astride the bar. In addition, to secure the blade, a coupling part can be attached to one end of the sleeve, which limits the free cross-section of the sleeve so that the blade cannot become detached.

Further features and advantages of the invention are revealed in the following description of exemplary embodiments, with reference to the attached figures, of which:

FIG. 1 shows a view of a refrigerator according to the invention, in which the outer side of the door of the refrigerator is visible;

FIG. 2 shows a perspective view of the refrigerator, in which the door is opened wide, so that its inner side is visible;

FIG. 3 shows a section through parts of a side wall and the door of the refrigerator along a plane denoted by III in FIG. 2.

FIG. 4 shows a section similar to that of FIG. 3 along a plane denoted by IV in FIG. 2.

FIG. 5 shows a partial sectional and partial perspective view of a pressure-compensating valve used in the refrigerator; and

FIG. 6 shows an enlarged detail of FIG. 1.

FIG. 1 shows a housing for a refrigerator with a body 1 and a door 2 hinged to the body and shown in a partially open position. A pressure-compensating valve 5 is arranged in a lower corner of the door 2 and extends between the front side and the rear side of the door 2.

FIG. 2 shows the same housing with the door 2 in a more widely opened position, in which its rear side facing the interior space 4 of the appliance is visible. A magnetic seal 26 in the form of a frame, which lies tightly against the frame 3 of the body 1 when the door 2 is closed, is arranged on the rear side.

To provide support to the magnetic seal 26, the frame 3 can be formed from a ferromagnetic sheet; by way of example, here the case is considered where the foam side of the frame 3 formed from plastic is backed by a strip 27 of ferromagnetic metal, the shape of which is shown by a dotted outline in FIG. 2. At the lower corner of the frame 3 the strip 27 has an inwards oriented bulge 28 which is opposite the pressure-compensating valve 5 when the door is closed.

FIG. 3 shows a section through a front area of a side wall of the body 1 and an adjacent area of the door 2 at the height of the plane denoted by III in FIG. 2. A chamber 29 of the magnetic seal 26 filled with magnetic material is opposite the strip 27 which is embedded in insulating foam material on the inner side of the frame 3. A refrigerant pipe 30 which extends all the way round the interior space 4 from a compressor (not shown) to a condenser (also not shown), is soldered to the rear side of the strip 27. When the compressor is in operation, warm refrigerant circulates in the refrigerant pipe 30 and heats the frame 3, primarily directly opposite the magnetic seal 26 and outside of this, via the magnetic seal 26, an edge region of the door 2.

FIG. 4 shows a section similar to that of FIG. 3 along the plane denoted by IV in FIG. 2. The intersecting plane runs through the pressure-compensating valve 5 and the bulge 28 opposite it. Heat delivered via the bulge 28 when the compressor is running, prevents freezing of the pressure-compensating valve 5.

FIG. 5 shows a partial sectional and partial perspective view of the pressure-compensating valve 5 and its surroundings. A piece of the metallic outer skin of the door 2 is denoted by 6. An inner skin is formed by a deep-drawn plastic shell which is bonded at its edges—not shown—to the metal sheet of the outer skin. A section of the inner container is denoted by 7.

An opening 9 which has the shape of a circle reduced by two segments on opposite sides, is cut into the base of a cavity 8 formed in the inner container 7. Before the inner container 7 is joined to the outer skin 6, a first sleeve 10 is introduced through the opening 9 from the side facing away from the observer, and locked into position. At its end facing the observer the sleeve 10 is provided with a flange 11 which, like the opening 9, has the shape of a circle with lateral segments removed and therefore is passed through the opening 9 with an orientation that is rotated by 90° with respect to the illustrated orientation, and is locked to said opening in the illustrated orientation.

In the configuration shown, the inner container 7 is clamped between the flange 11 and a flexible annular flange 12 pressed against the side of the inner container 7 facing the outer skin. The external diameter of the annular flange 12 is greater than that of the opening 9, so that insulating material—not shown in FIG. 2—that fills the space between the outer skin 6 and the inner container 7 cannot reach the opening 9.

A second annular flange 13 of a smaller diameter than that of the first annular flange 12 is formed on the sleeve 10 adjacent to its end facing the outer skin 6. This annular flange 13 makes flexible contact with the inside of a widened conical section 14 of a second sleeve 15. The sleeve 15 is attached to the outer skin 6 in the same way as the sleeve 10 by clamping it between a flange 16 fitted to the outside of the outer skin 6, and a flexible annular flange 17 fitted to the inside. During assembly, the elasticity of the annular flange 13 allows displacement of the two sleeves 10, 15 with respect to each other, thereby providing compensation for a variable door thickness.

The sleeve 15 is also fitted to the outer skin 6 before its assembly with the inner container 7. When the outer skin 6 and the inner container 7 are being joined together, the widened shape of the section 14 assists the entry of the sleeve 10 into the sleeve 15.

A short cylindrical section 18 of the sleeve 15 in which the sleeve 10 is positively held, is attached to the section 14.

The free end of the sleeve 10 extends into a cup-shaped widening 19 of the sleeve 15, which is attached to the cylindrical section 18 and which supports the flange 16 and the annular flange 17.

Due to the displacement in the conical section 14, the annular flange 13 of the sleeve 10 is flexibly bent back so that the surface of the annular flange 13 facing the insulation material assumes a concave shape. Thus, when pressure is applied when the hollow space between the outer skin 6 and the inner container 7 is being filled with foam, the annular flange 13 is pressed against the conical section 14, which further improves the sealing effect of the annular flange 13.

The interior of the sleeve 10 is divided diametrically by a longitudinal wall 20. A flexible plastic blade 21 is mounted astride the longitudinal wall 20. The blade 21 has an essentially elliptical shape, so that its edges are able to mould themselves very closely to the sleeve 10 along their entire length. In the event of an underpressure in the interior space 4, the edges of the blade 21 are pressed against the longitudinal wall 20 and air can flow from the outside to the inside. Any overpressure in the interior space 4 acts against the entire surface of the blade 21 and presses this outwards or against the sleeve 10. A coupling part 22 anchored at the free end of the sleeve 10 by means of a bayonet coupling—not shown in detail—prevents the blade 21 from being pushed out of the sleeve 10 by the internal overpressure; on the one hand by the coupling part 22 narrowing the free end cross-section of the sleeve 10, and on the other hand by a transverse bar 23 which extends diametrically through a central opening 24 of the coupling part 22.

The widening 19 of the sleeve 15 with the flange 16 fitted to the outside of the outer skin 6, parts of an opening 25 in the outer skin into which the sleeve 15 is inserted, as well as the coupling part 22 inside the widening 19, can be seen in the external view of the valve shown in FIG. 6. 

1-16. (canceled)
 17. A refrigerator with a body and a door attached to the body wherein the body and the door delimit a thermally-insulated interior space, the refrigerator comprising a pressure-compensating valve for controlling an inflow of air from the outside of the refrigerator into the interior space and an outflow of air to the outside of the refrigerator out of the interior space to the outside of the refrigerator, wherein the pressure-compensating valve is disposed in thermal contact with a heat source and for heating the pressure-compensating valve to a temperature greater than the freezing point of water.
 18. The refrigerator according to claim 17 wherein the heat source is configured as electrical resistance heating.
 19. The refrigerator according to claim 17 wherein the heat source is configured as piping on an output side of a compressor of a compressed refrigerant circuit.
 20. The refrigerator according to claim 17 wherein the heat source is configured as a frame heating apparatus for a front frame of the body facing the door, and that the pressure-compensating valve is in thermal contact with the frame heating apparatus for enabling the pressure-compensating valve to achieve a temperature greater than the freezing point of water.
 21. The refrigerator according to claim 17 wherein the pressure-compensating valve is mounted in an area of the door opposite the frame.
 22. The refrigerator according to claim 21 wherein the frame includes a ferromagnetic strip disposed opposite a magnetic seal mounted to the door, and that the ferromagnetic strip has a locally widened section in an area opposite the pressure-compensating valve.
 23. The refrigerator according to claim 17 wherein the pressure-compensating valve is mounted in one corner of the door.
 24. The refrigerator according to claim 17 wherein the frame heating apparatus includes piping through which compressed refrigerant passes.
 25. The refrigerator according to claim 17 wherein the pressure-compensating valve is inserted into one wall of at least one of the body and the door, each of which includes a solid outer wall, a solid inner wall and a layer of insulating material enclosed therebetween, wherein the pressure-compensating valve is disposed in operative association with a tube passing through the layer of insulation material and sealed at the outer wall and the inner wall, said tube having two interlocking sleeves, including a first sleeve that is attached to the outer wall and a second sleeve that is attached to the inner wall.
 26. The refrigerator according to claim 25 wherein the outer sleeve is formed with a conical inlet section into which the inner sleeve is inserted and which opens into the layer of insulating material.
 27. The refrigerator according to claim 25 wherein the outer sleeve encloses at least a portion of the length of the inner sleeve, wherein the inner sleeve is enclosed by a first annular lip fitted to the outer sleeve.
 28. The refrigerator according to claim 27 wherein the first annular lip is concave on one side facing the layer of insulating material.
 29. The refrigerator according to claim 25 wherein at least one of the sleeves passes through an opening of at least one of the outer wall and the inner wall to which the respective sleeve is attached, wherein the respective sleeve supports projections located at one outer side of at least one of the outer wall and the inner wall, and a second annular lip is located at one inner side of at least one of the outer wall and the inner wall facing the insulation material layer.
 30. The refrigerator according to claim 25 wherein the valve includes a bent flexible blade disposed in the inner sleeve and having edges in contact with the inside of the inner sleeve.
 31. The refrigerator according to claim 30 and further comprising a bar extending diametrically through the inner sleeve wherein the blade sits astride the bar.
 32. The refrigerator according to claim 30 wherein the blade is secured in the inner sleeve by a coupling part attached to one end of the sleeve wherein said coupling part limits the free cross-section of the sleeve. 